Washington ? The first color pictures from the NASA space probe expedition to Mars have now been published. They look like — well, they look like pictures of a lifeless, distant planet. They show blank, empty landscapes. They show craters and boulders. They show red sand. Death Valley, the most desolate of American deserts, at least contains strange cacti, vicious scorpions, the odd oasis. Mars has far less than that. Not only does the planet have no life, it has no air, no water, no warmth. The temperature on the Martian surface hardly rises above zero degrees Fahrenheit and can drop several hundred degrees below that.

Mars, as a certain pop star once put it, isn’t the kind of place where you’d want to raise your kids. Nor is it the kind of place anybody is ever going to visit, as some of the NASA scientists know perfectly well. Even leaving aside the cold, the lack of atmosphere and the absence of water, there’s the deadly radiation. If the average person on Earth absorbs about 350 millirems of radiation every year, an astronaut traveling to Mars would absorb about 130,000 millirems of a particularly virulent form of radiation that would probably destroy every cell in his body. “Space is not ‘Star Trek,’ ” said one NASA scientist, “but the public certainly doesn’t understand that.”

No, the public does not understand that. And no, not all scientists, or all politicians, are trying terribly hard to explain it either. Too often, rational descriptions of the inhuman, even anti-human living conditions in space give way to public hints that more manned space travel is just around the corner, that a manned Mars mission is next, that there is some grand philosophical reason to keep sending human beings away from the only planet where human life is possible. One actual “Star Trek” actor, Robert Picardo, the ship’s holographic doctor, enthused this week that “we really should have a timetable to send a man to Mars. … Mars should be part of our travel plans.” Naive, perhaps, but fundamentally not much different from President Bush’s grandiloquent words after the Columbia disaster: “Mankind is led into the darkness beyond our world by the inspiration of discovery and the longing to understand. Our journey into space will go on.”

But why should it go on? Or at least why should the human travel part of it go on? Crowded out of the news this week was the small fact that the troubled international space station, which is itself accessible only by the troubled space shuttle, has sprung a leak. Also somehow played down is the fact that the search for “life” on Mars — proof, as the enthusiasts have it, that we are “not alone” in the universe — is not a search for sentient beings but rather a search for evidence that billions of years ago there might possibly have been a few microbes. It’s hard to see how that sort of information is going to heal our cosmic loneliness, let alone lead to the construction of condo units on Mars.

None of which is to say that it isn’t interesting or important for NASA to send robotic probes to other planets. It’s interesting in the way that the exploration of the bottom of the Pacific Ocean is interesting, or important in the way that the study of obscure dead languages is important. Like space exploration, these are inspiring human pursuits. Like space exploration, they nevertheless have very few practical applications.

But space exploration isn’t treated the way other purely academic pursuits are treated. For one, the scientists doing it have perverse incentives. Their most dangerous missions — the ones involving human beings — produce the fewest research results, yet receive the most attention, applause and funding. Their most productive missions — the ones involving robots — inspire interest largely because the public illogically believes they will lead to more manned space travel.

Worse, there is always the risk that yet another politician will seize on the idea of “sending a man to Mars,” or “building a permanent manned station on the moon” as a way of sounding far-sighted or futuristic or even patriotic. President Bush is allegedly considering a new expansion of manned space travel. The Chinese are embarking on their own manned space program, since sending a man to the moon is de rigueur for would-be superpowers. The result, inevitably, will be billions of misspent dollars, more lethal crashes — and a lot more misguided rhetoric about the “inspiration of discovery,” as if discoveries can only be made with human hands.